What you need to know about Covid-19 reinfection

As we head further from the peak of the vaccine campaign and the Omicron outbreak, people’s immunity will eventually start to wane. The coronavirus is also continuing to mutate, with subvariants like BA.4 potentially making it easier for people to be reinfected.

Does reinfection increase the risk of Long Covid?

University of Auckland Dr Anna Brooks says “we are hearing from our international partners that anecdotally, repeat infections, especially in children and adolescents may lead to a higher chance of long term health complications, including Long Covid.

“We know that vaccinations are excellent at protecting against severe illness, however they aren’t great at reducing the risk of Long Covid. Protective immunity will also wane over time. Symptomatic infections, even while triple vaccinated are common. vaccinated is the best way to avoid the risk of developing long term health complications.”

New Covid-19 variants and waning immunity could see more New Zealanders catching the virus for a second time

“In addition, surviving one infection unscathed does not mean you will be out of the woods with getting Long Covid. It might be a 2nd or 3rd exposure that triggers this illness.

“Many also don’t seem to realise that there are no treatments to reverse the debilitating symptoms experienced (shortness of breath, brain fog/cognitive impairment, extreme fatigue to name a few).

“Limiting exposure to the virus, even if previously infected and/or fully

If you’ve already had Covid-19, how well are you protected from getting it again?

The figure of three months of immunity is largely a generalisation, Brooks says.

“Cases of reinfection are definitely occurring within this time frame. Even if you’ve had Covid, you may have fairly decent immunity for at least a month or so, but you’re certainly not immune to further infections in the near future. The best approach is to avoid exposure, regardless of your vaccination or preinfection status.”

University of Otago Dr Dianne Sika-Paotonu says many who’ve recovered from Covid-19 will have developed immunity at least for the initial months following infection, however re-infection risk with the SARS-CoV-2 virus remains.

“Although previous infection with the SARS-

Long Covid

Long Covid presents a considerable challenge for employers because key workers may have difficulty returning to their normal jobs within usual timescales.

There remain important questions for workers, employers and their occupational health advisors: • What are the functional limitations of an individual worker with any condition including Long Covid? • What are the task requirements of their job? • What are their specific limitations in relation to their job? • What is the likely trajectory of their recovery? • What flexibility, adjustments or modifications can be made to the job or the working hours? • Does the work organisation provide access to occupational health and rehabilitation services such as physiotherapy or mental health support? • Are there any safety-critical issues to be considered?

If a worker with Long Covid has complex health issues that are preventing their return to work, an occupational health assessment will be necessary to identify their work ability and their limitations. This may involve communication with the worker’s personal physician, providing there is consent given to do so.

Employing organisations normally have sickness absence policies that have various triggers and thresholds for the level of absence from work, or incapacity that can be accommodated. For workers with Long Covid, these triggers may however not be appropriate as recovery may be very slow because of fatigue or other symptoms, and modification of these policies may need to be considered and timescales extended.

Most workers recovering from Long Covid will require a slow, phased return to work, beginning with a small amount of work every day and every week, and gradually extending working hours over a period of one to two months or longer.

To reduce the risk of relapses, workers should not be doing more than 70% of what they feel capable of doing at any time in order to avoid fatigue. Becoming fatigued can cause relapses in their condition and further delay their recovery.

The worker is the person who can best assess their own level of fatigue and regular discussion between worker and manager is important to guide the successful rehabilitation of workers affected by Long Covid. As in any positive working relationship, trust between employees and managers plays a significant role for effective adaptation of work.

This will not always be successful and a small number of Long Covid workers have had to retire from work on the grounds of ill health. However, a number of individuals have also been retired by their employers, who with more time may have been rehabilitated for work.

osha.europa.eu

CoV-2 virus does offer some immune protection, this does wane over time.

“Importantly, recent evidence is indicating re-infections have been increasing with the Omicron variant of the SARS-CoV-2 virus.”

Will a second infection make someone more, less, or just as sick as the first time?

In the UK, Covid-19 reinfection estimates from their Office for National Statistics indicated that reinfections with the Alpha variant produced symptomatic Covid-19 in 20% of cases, while reinfections with the Delta variant caused symptoms in 44% of cases. For Omicron, 46% of cases had symptomatic Covid-19 (-reinfections were defined as 120 days between positive tests or 4 subsequent negative PCR tests between infections).

“This data showed that people reinfected with the Alpha variant were much less likely to get symptoms the second time, when compared to their primary infection. Delta and Omicron reinfections however were more likely to cause people to experience symptoms,” Sika-Paotonu says.

“One study from Qatar looking at the re-infection severity after initial infection with the Alpha and Beta variants indicated that overall, SARS-CoV-2 reinfections (i.e. another infection occurring at least 90 days after the 1st infection), tended to be less severe when compared with the primary infection.

“Ongoing work will be needed to understand more about whether re-infections for Omicron and all its subvariants are more or less severe, when compared to the primary infection. It is still important that those who may have already had a Covid-19 infection, strengthen their immunity with vaccination as well.”

Do variants and subvariants increase the chance of reinfection?

“A study from Imperial College London based on the UK Health Security Agency and National Health Service data showed that the risk of re-infection with Omicron was more than 5 times higher when compared with Delta,” SikaPaotonu says.

“Monitoring for new variants will be important moving forward particularly with further easing of border restrictions, and will be especially important for managing potential future outbreaks caused by any new variants arising overseas. Community spread in Aotearoa New Zealand will be rapid if any new variants appear that are resistant to current Covid-19 vaccines.

“While issues with unequal global Covid-19 vaccine coverage, availability, accessibility and distribution persist, and remain unaddressed, new variants will continue to emerge, develop and spread.”